#include <iostream>
#include <vector>
using namespace std;
int main(){
    int n,m;
    cin >> n >> m;
    vector<int> apples(n), taotaos(m);
    for(auto apple : apples){
        cin >> apple;
    }
    for(auto taotao:taotaos){
        cin >> taotao;
    }
    sort(apples.begin(),apples.end());
    sort(taotaos.begin(),taotaos.end());
    int snaped = 0, apple_cur = 0;
    for(auto taotao : taotaos){
        if(apples[apple_cur++] >= taotao) snaped++;
    }
    cout << m - snaped;
    return 0;
}